Methods and apparatuses for determining a phase tracking reference signal configuration parameter

ABSTRACT

Embodiments of the present disclosure relate to methods, terminal device, network device and apparatuses for determining a Phase Tracking Reference Signal (PTRS) configuration parameter. In an embodiment of the present disclosure, the method of interference measurement comprises determining a PTRS transmission resource configuration parameter based on a resource allocation type to be used in data transmission. With embodiments of the present disclosure, it may determine different PTRS configuration parameters for different resource allocation types, and thus provide a more suitable PTRS configuration solution for different resource allocation cases.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.16/637,845 filed Feb. 10, 2020 which is a National Stage ofInternational Application No. PCT/CN2017/097294 filed Aug. 12, 2017, thecontents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The non-limiting and exemplary embodiments of the present disclosuregenerally relate to the field of wireless communication techniques, andmore particularly relate to a method, terminal device and apparatus fordetermining a Phase Tracking Reference Signal (PTRS) configurationparameter at terminal device and a method, network device, apparatus fordetermining PTRS configuration parameter at a network device.

BACKGROUND OF THE INVENTION

New radio access system, which is also called as NR system or NRnetwork, is the next generation communication system. In Radio AccessNetwork (RAN) #71 meeting for the third generation Partnership Project(3GPP) working group, study of the NR system was approved. The NR systemwill consider frequency ranging up to 100 Ghz with an object of a singletechnical framework addressing all usage scenarios, requirements anddeployment scenarios defined in Technical Report TR 38.913, whichincludes requirements such as enhanced mobile broadband, massivemachine-type communications, and ultra-reliable and low latencycommunications.

Discussion of multi-antenna scheme for new radio access started from Mayin 2016, including following aspects:

-   -   Multi-antenna scheme    -   Beam management    -   channel state information (CSI) acquisition    -   Reference signal and Quasi-Colocation (QCL)

In the NR system, it was already agreed to introduce Phase TrackingReference Signal (PTRS) to track phase noise, especially for higherfrequency bands. It was also agreed that the PTRS is associated with oneDemodulation Reference Signal (DMRS) in a DMRS port group and theassociation can determined in the specification.

In the NR system, the PTRS density is associated with scheduledModulation and Coding Scheme (MCS)/Band Width (BW). Specifically, thePTRS time density is associated with scheduled MCS while the PTRSfrequency density is associated with the scheduled BW.

In 3GPP technical document R1-1709521, there were proposed associationsbetween the PTRS and scheduled MCS/BW. Particularly, in R1-1709521, itwas proposed that for Single User Multiple-Input Multiple-Output(SU-MIMO), it supports predefined and RRC-configured association betweenPTRS densities and scheduled MCS/BW. Table 1 as illustrated in FIG. 1Ais used to represent association between PTRS time density and scheduledMCS and Table 2 as illustrated in FIG. 1B was used to representassociation between PTRS frequency density and scheduled BW. The numberof rows in Tables 1 and 2 can be reduced if the densities aredown-selected. In addition, whether RRC configuration can override thepredefined association, whether UE is to suggest MCS/BW thresholds ofassociation tables as illustrated in FIGS. 1A and 1B and complementaryDownlink Control Information (DCI) signaling are for further study.

SUMMARY OF THE INVENTION

In the existing solution of the NR system, the PTRS frequency density isassociated with scheduled MCS/BW only. However, such a solution cannotmeet requirements for different scenarios.

To this end, in the present disclosure, there is provided an improvedsolution of interference measurement to mitigate or at least alleviateat least part of the issues in the prior art.

According to a first aspect of the present disclosure, there is provideda method for determining a Phase Tracking Reference Signal (PTRS)configuration parameter at a terminal device. The method may comprisedetermining a PTRS transmission resource configuration parameter basedon a resource allocation type to be used in data transmission.

According to a second aspect of the present disclosure, there isprovided a method for determining a Phase Tracking Reference Signal(PTRS) configuration parameter at a network device. The method maycomprise determining a PTRS transmission resource configurationparameter based on a resource allocation type to be used in datatransmission.

According to a third aspect of the present disclosure, there is provideda terminal device. The terminal device may comprise a controller,configured to determine a PTRS transmission resource configurationparameter based on a resource allocation type to be used in datatransmission.

According to a fourth aspect of the present disclosure, there isprovided a network device. The network device may comprise a controllerconfigured to determine a PTRS transmission resource configurationparameter based on a resource allocation type to be used in datatransmission.

According to a fifth aspect of the present disclosure, there is provideda computer-readable storage media with computer program codes embodiedthereon, the computer program codes being configured to, when executed,cause an apparatus to perform actions in the method according to anyembodiment in the first aspect.

According to a sixth aspect of the present disclosure, there is provideda computer-readable storage media with computer program codes embodiedthereon, the computer program codes being configured to, when executed,cause an apparatus to perform actions in the method according to anyembodiment in the second aspect.

According to a seventh aspect of the present disclosure, there isprovided a computer program product comprising a computer-readablestorage media according to the fifth aspect.

According to an eighth aspect of the present disclosure, there isprovided a computer program product comprising a computer-readablestorage media according to the sixth aspect.

With embodiments of the present disclosure, it may determine differentPTRS configuration parameters for different resource allocation types,and thus provide a more suitable PTRS configuration solution fordifferent resource allocation cases.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present disclosure will become moreapparent through detailed explanation on the embodiments as illustratedin the embodiments with reference to the accompanying drawings,throughout which like reference numbers represent same or similarcomponents and wherein:

FIGS. 1A and 1B schematically illustrate association tables between PTRSdensity and scheduled BW/MCS in the prior art;

FIGS. 2A to 2C schematically illustrate example resource allocationtypes might be used in the NR system;

FIG. 3 schematically illustrates a flow chart of a method fordetermining PTRS configuration parameters at a terminal device accordingto an embodiment of the present disclosure;

FIGS. 4A to 4C schematically illustrate example association tables ofPTRS configuration parameters for different resource allocation typesaccording to embodiments of the present disclosure;

FIG. 5 schematically illustrates another example association solutionaccording to embodiments of the present disclosure;

FIG. 6A to 6C schematically illustrate further example associationsolutions according to embodiments of the present disclosure;

FIG. 7 schematically illustrates a flow chart of a method fordetermining a PTRS configuration parameter at a network device accordingto an embodiment of the present disclosure;

FIG. 8 schematically illustrates a diagram of PTRS transmission in ascenario wherein UE is served by multiple Transmission and ReceptionPoints (TRPs);

FIG. 9 schematically illustrates a PTRS transmission solution in thescenario wherein the UE is served by multiple TRPs according to anembodiment of the present disclosure;

FIGS. 10A and 10B schematically illustrate another PTRS transmissionsolution in the scenario wherein the UE is served by multiple TRPsaccording to an embodiment of the present disclosure;

FIG. 11 schematically illustrates a further PTRS transmission solutionin the scenario wherein the UE is served by multiple TRPs according toan embodiment of the present disclosure;

FIG. 12 schematically illustrates a block diagram of an apparatus fordetermining a PTRS configuration parameter at a terminal deviceaccording to an embodiment of the present disclosure;

FIG. 13 schematically illustrates a block diagram of an apparatus fordetermining a PTRS configuration parameter at a network device accordingto an embodiment of the present disclosure;

FIG. 14 further illustrates a simplified block diagram of an apparatus1410 that may be embodied as or comprised in a network device (likegNB), and an apparatus 1420 that may be embodied as or comprised in aterminal device like UE as described herein.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, the solution as provided in the present disclosure will bedescribed in details through embodiments with reference to theaccompanying drawings. It should be appreciated that these embodimentsare presented only to enable those skilled in the art to betterunderstand and implement the present disclosure, not intended to limitthe scope of the present disclosure in any manner.

In the accompanying drawings, various embodiments of the presentdisclosure are illustrated in block diagrams, flow charts and otherdiagrams. Each block in the flowcharts or blocks may represent a module,a program, or a part of code, which contains one or more executableinstructions for performing specified logic functions, and in thepresent disclosure, a dispensable block is illustrated in a dotted line.Besides, although these blocks are illustrated in particular sequencesfor performing the steps of the methods, as a matter of fact, they maynot necessarily be performed strictly according to the illustratedsequence. For example, they might be performed in reverse sequence orsimultaneously, which is dependent on natures of respective operations.It should also be noted that block diagrams and/or each block in theflowcharts and a combination of thereof may be implemented by adedicated hardware-based system for performing specifiedfunctions/operations or by a combination of dedicated hardware andcomputer instructions.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the/said [element,device, component, means, step, etc.]” are to be interpreted openly asreferring to at least one instance of said element, device, component,means, unit, step, etc., without excluding a plurality of such devices,components, means, units, steps, etc., unless explicitly statedotherwise. Besides, the indefinite article “a/an” as used herein doesnot exclude a plurality of such steps, units, modules, devices, andobjects, and etc.

Additionally, in a context of the present disclosure, a user equipment(UE) may refer to a terminal, a Mobile Terminal (MT), a subscriberstation, a portable subscriber station, Mobile Station (MS), or anAccess Terminal (AT), and some or all of the functions of the UE, theterminal, the MT, the SS, the portable subscriber station, the MS, orthe AT may be included. Furthermore, in the context of the presentdisclosure, the term “BS” may represent, e.g., a node B (NodeB or NB),an evolved NodeB (eNodeB or eNB), gNB (Node B in NR system), a radioheader (RH), a remote radio head (RRH), a relay, or a low power nodesuch as a femto, a pico, and so on.

As mentioned in Background, the PTRS frequency density is associatedwith scheduled MCS/BW only; however such a solution cannot meetrequirements for different scenarios. For example, in the NR system, itwas already agreed to use Long Term Evolvement LTE Type 0 and Type 2allocation as the resource allocation schemes in the NR system. In thefrequency domain, for Physical Uplink Shared Channel (PUSCH) withDiscrete Fourier Transform spread Orthogonal Frequency DivisionMultiplexing DFT-s-OFDM waveform in the NR, system, contiguous resourceallocation scheme based on LTE UL RA Type 0 is adopted in Rel. 15. Acoarser granularity (i.e. more than 1 RB) of resource assignment inorder to reduce the overhead further and BW parts are still remained forfurther study. A DCI format with resource allocation based on LTEDownlink (DL) RA type 0 (i.e., bit-map) and a DCI format with resourceallocation based on LTE DL RA type 2 are supported for Physical DownlinkShared Channel (PDSCH). A DCI format with resource allocation based onLTE DL RA type 0 (i.e., bit-map) is supported for PUSCH with CyclicPrefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform anda DCI format with resource allocation based on LTE uplink (UL) RA type 0is supported for PUSCH with CP-OFDM waveform and with DFT-s-OFDMwaveform. Whether some or all of the above DCI formats have the same DCIpayload size is for further study.

Thus, it can be seen that for the DCI format, the NR system at leastsupports two RA types, i.e., RA types 0 and RA type 2, and the LTE UL RAtype 0 and LTE DL RA type 0 are also different. For illustrationpurposes, references will be made to FIG. 2A to 2C to describe the RAtypes in brief.

As illustrated in FIG. 2A, the system bandwidth comprises for example 50physical resource blocks (PRBs). For RA type 0, the system bandwidthwill be divided into 17 subband each containing three PRBs except thelast RBG which contains only 2 PRBs. In RA type 0, the resourceallocation is based on the subband, and a bit map of 17 bits will beused to indicate resource allocation and FIG. 2B illustrates an exampleresource allocation using RA Type 0. For RA type 2, the resourceallocation is based on PRBs, and there are two allocation modes,continuous mode (or localized mode) and distributed mode. In thecontinuous mode, a segment of continuous PRBs will be allocated asillustrated in FIG. 2C; while in the distributed mode, the allocated PRBindexes are continuous but they will be mapped to the transmissionresource with a certain gap.

However, as already mentioned, in the NR system, the PTRS frequencydensity is associated with scheduled MCS/BW/SCS only and thus such aPTRS association is not suitable.

In order to address or at least mitigate the above problem, in thepresent disclosure, there is proposed an improved solution of PTRSconfiguration. For illustrative purposes, reference will be made toFIGS. 3 to 7 and 12 to 14 to describe the solution of determining PTRSconfiguration parameters as proposed in the present disclosure. It shallbe appreciated that all embodiments are given for illustrative purposesand the present disclosure is not limited thereto.

FIG. 3 schematically illustrates a flow chart of a method 100 fordetermining a PTRS configuration parameter at a terminal deviceaccording to an embodiment of the present disclosure. The method 300 canbe performed at a terminal device, for example UE, or other liketerminal devices.

As illustrated in FIG. 3 , first in step 301, the terminal device maydetermine a PTRS transmission resource configuration parameter based ona resource allocation type to be used in data transmission.

The term “PTRS transmission resource configuration parameter” usedherein refers to a configuration parameter for the PTRS transmissionresource, which can include for example, PTRS frequency density, PTRSresource table, PTRS resource mapping, PTRS transmission positions, etc.The term “resource allocation type” used herein refers to the manner inwhich the resource is allocated, which for example, include RA type 0,RA type 2, etc. However, it shall be understood that the RA types arenot limited to these; instead, the NR system might support new RA typesor other RA types different from those listed. In fact, the presentdisclosure can be applied to all of these RA types, but hereinafter, forillustration purposes, RA Type 0 and Type 2 will be taken as examples.

It can be appreciated that the PTRS frequency density/presenceassociation only considers number of PRBs or scheduled BW, there may besome issues for different resource allocation types. For example, forthe 50 RBs, one RA scheme is to adopt RA type 2 with localizedallocation and 17 continuous RBs is allocated, as illustrated in FIG.2C); in such case, the PTRS frequency density is e.g. ¼, and thenperhaps 4 RBs with PTRS are enough. While for the other RA scheme of RAtype 0 with the subband size of 3, if 17 RBs is allocated (for example,as illustrated in FIG. 2B), if the subband interval in frequency domainis large, 4 RBs with PTRS are not insufficient and more RBs with PTRSmight be needed. Thus, in the NR system, it is proposed to use differentPTRS transmission resource configuration parameters for differentresource allocation types.

The network device may indicate the resource allocation type to theterminal device in any suitable manner. For example, the resourceallocation type can be dynamically indicated in DCI. Based on thedetected RA type, for example, it can select a table corresponding tothe detected RA type.

In an embodiment of the present disclosure, the terminal device maydetermine an association table corresponding to the resource allocationtype from a plurality of association tables of PTRS transmissionresource configuration parameter for a plurality of resource allocationtypes. Additionally, the terminal device may further obtain the PTRStransmission resource configuration parameter from the associationtable.

The plurality of association tables can be predetermined tables in theterminal device. Or alternatively, these tables may be configured in ahigher layer signaling, e.g. via Radio Resource Control (RRC) signalingor Media Access Control Control Element (MAC CE). Thus, in step 302, theterminal device may further receive configuration information on theplurality of association tables of PTRS transmission resourceconfiguration parameter from a network device. The configurationinformation can be new configuration information or configuration updateinformation. Thus, the operation recited in step 302 can be performedbefore step 301 or after step 301.

Next, for illustration purposes, reference will be made to FIGS. 4A to4C to describe example association tables for the PTRS configurationparameters. As illustrated in FIGS. 4A to 4C, there are provided threetables, Table 2, Table 3A and Table 3B, respectively for RA Type 0, RAtype 2 in localized mode, and RA Type 2 in distributed mode.

Specifically, for RA type 0, the PTRS frequency density can be based onTable 2. For example, the PTRS frequency density can be associated withscheduled BW or number of PRBs. In addition, it shall be understand,additionally or alternatively, the PTRS frequency density can beassociated with the size of the resource segment, i.e. the number of thecontinuous PRB, or the size of RBG For example, for each RBG there isone PTRS. For RA type 2, the PTRS frequency density can be based on adifferent table from Table 2. For example, the PTRS frequency densitymay be associated with scheduled BW, e.g. number of PRBs. For RA type 2with localized mode, the PTRS frequency density is based on Table 3A andFor RA type 2 with distributed mode, the PTRS frequency density is basedon Table 3B. From the three tables, it can be seen that both respectivePTRS frequency densities and thresholds for using PTRS can be different.In addition, for RA Type 2, for different resource allocation modes (forexample, the localized allocation and the distributed allocation), theycan be configured with different tables. For example, for a given numberof PRBs, the frequency density for localized allocation mode may besmaller than that for distributed allocation mode.

It shall be noted that the tables as illustrated in FIG. 4A to 4C arejust given for illustration purposes and the present disclosure is notlimited thereto. There can be other options for designing theassociation tables. For example, it is also possible that Type 2 withthe distributed mode can share the common table with RA type 0. Asanother example, it is also possible that RA type 0 can be divided intodifferent allocation modes which could use different association tables.For example all possible patterns of the bitmap can be divided to twoallocation modes, those with continuous or localized allocation, andthose with distributed allocations. Further, those distributedallocations can be further divided based on the distributed degree. Insuch a case, it may use more association tables for differentdistributed modes.

In another embodiment of the present disclosure, the terminal device maydetermine a resource mapping corresponding to the resource allocationtype from a plurality of resource mappings of PTRS transmission for aplurality of resource allocation types. Further, it is also possible tofurther obtain the PTRS transmission resource configuration parameterbased on the resource mapping. As an example, it may use differentmapping schemes for different RA types. For example, there can be amapping scheme for RA type 0, another mapping scheme for RA type 2 withlocalized mode, and a further mapping scheme for RA type 2 withdistributed mode. That is to say, different mapping schemes are used fordifferent RA types and the plurality of resource mappings furthercomprises different resource mappings for different allocation modes inthe same resource allocation type.

It is also possible to adopt other mapping schemes. For example, it isalso possible that Type 2 with distributed mode can share the commonmapping scheme with RA type 0. As another example, it is also possiblethat RA type 0 can be divided into different allocation modes whichcould use different mapping schemes. For example all possible patternsof the bitmap can be divided to two allocation modes, those withcontinuous or localized allocation, and those with distributedallocations. Further, those distributed allocations can be furtherdivided based on the distributed degree. In such a case, it may use moremapping schemes for different distributed modes.

In a further embodiment of the present disclosure, the PTRS transmissionresource configuration parameter can be associated with sizes ofrespective resource segments within allocated transmission resources.For example, for RA Type 0 (bitmap), the PTRS frequency density can beassociated with the size of the resource segment, i.e. the number of thecontinuous PRB, or the size of RBG

In an embodiment of the present disclosure, the resource segments can bedivided into different kinds, each of which is configured with differentmapping schemes. For example, the resource segment can be divided intoisolated segments, and close or continuous segment, as illustrated inFIG. 5 . Those resource segments containing only one subband can beidentified as isolated segment while those containing more than onesubband can be identified as close segment. In such a case, for anisolated segment, at least one PTRS is mapped on the RBG; whereas for acontinuous or close segment, the PTRS can be mapped based on the densityassociation table but the scheduled BW is based on the continuous numberof RBs instead of the number of totally scheduled RBs.

It shall be noted that FIG. 5 is just given for illustration purposesand the skilled in the art is not limited thereto. The identificationrules of the isolated segment and the close or continuous segment can bechanged based on requirements. For example, those resource segmentscontaining one or two subbands can be identified as isolated segmentwhile those resource segments containing more than two subbands can beidentified as close segment.

In another embodiment of the present disclosure, the PTRS frequencydensity can also be associated with the distance between two adjacentresource segments. For example, it may set a distance threshold d. Ifthere are less than d PRBs between two adjacent resource segments, thenthe PTRS will have a low frequency density, while if there are more thand PRBs therebetween, the PTRS will have a high frequency density.

In another embodiment of the present disclosure, the PTRS frequencydensity can be associated with a common index table with a continuousmapping. In other word, the common index table together indicates allpotential PTRS positions, as illustrated in FIG. 6A. For different RAtypes, it may use different mapping schemes. For example, for RA type 2with the localized allocation, the PTRS can be directly mapped onto RBsbased on the common index table, as illustrated in FIG. 6B. On thecontrary, for RA type 0 (bitmap), the PTRS can be mapped onto RBsoverlapped with the potential positions as indicated in the common indextable, as illustrated in FIG. 6C. Thus, although the PTRS density is thesame for all types but the mappings are different and the PTRS can stillmeet requirements of different cases.

In addition, different PTRS assumptions can be used for differentconfigurations. Herein, configurations include for example, RadioNetwork Temporary Identity (RNTI) of PDCCH, resource allocation types orthe combination thereof. For example, RNTI may include various types,like Random access Radio Network Temporary Identity (RA-RNTI), SystemInformation Radio Network Temporary Identity (SI-RNTI), Paging RadioNetwork Temporary Identity (P-RNTI), Cell Radio Network TemporaryIdentity (C-RNTI). For those with low MCS, PTRS may not be transmitted.As an example, for RA-RNTI, SI-RNTI, P-RNTI, there is no need for PTRS,while for the C-RNTI, the PTRS can be used.

Hereinbefore, the PTRS parameter determination solution at the terminaldevice is described with reference to embodiments of the presentdisclosure and next the PTRS parameter determination solution at thenetwork device will be described with reference to FIG. 7 .

FIG. 7 illustrates a flow chart of method of determining PTRStransmission resource configuration parameter at the network deviceaccording to an embodiment of the present disclosure. As illustrated inFIG. 7 , first in step 701, the network device in the NR system, likegNB, may determine a PTRS transmission resource configuration parameterbased on a resource allocation type to be used in data transmission. ThePTRS transmission resource configuration parameter may include forexample, PTRS frequency density, PTRS resource table, PTRS resourcemapping, PTRS transmission positions, etc. Similarly to the terminaldevice side, at the network device, it is also proposed to use differentPTRS transmission resource configuration parameter for differentresource allocation type.

The network device may determine the resource allocation type to be usedand indicate the resource allocation type to the terminal device in anysuitable manner. For example, the network device may contain theresource allocation type information in DCI and transmit the DCI to theterminal device dynamically. Based on the resource allocation type, thenetwork device can select a table corresponding to the detected RA type.

In an embodiment of the present disclosure, the network device maydetermine an association table corresponding to the resource allocationtype from a plurality of association tables of PTRS transmissionresource configuration parameter for a plurality of resource allocationtypes. Additionally, the network device may further obtain the PTRStransmission resource configuration parameter from the associationtable.

The plurality of association tables can be predetermined tables in thenetwork device; or alternatively, these tables may be variable and areconfigured in a higher layer signaling, e.g. via RRC signaling or MACCE, etc. Thus, in step 702, the network device may further transmitconfiguration information on the plurality of association tables of PTRStransmission resource configuration parameter to a terminal device.

For example association tables, reference can be made to FIGS. 4A to 4Cand related description. In the plurality of association tables, it mayfurther comprise different association tables configured for differentallocation modes in the same resource allocation type. For example, forRA Type 2, for different resource allocation modes, for example, thelocalized allocation and the distributed allocation, different tablescan be used.

There can be other options for designing the association tables. Forexample, it is also possible that Type 2 with distributed mode can sharethe common table with RA type 0. As another example, it is also possiblethat RA type 0 can be divided into different allocation modes whichcould use different association tables. For example, all possiblepatterns of the bitmap can be divided to two allocation modes, thosewith continuous or localized allocation, and those with distributedallocations. Further, those distributed allocations can be furtherdivided based on the distributed degree. In such a case, it may use moreassociation tables for different distributed modes.

In another embodiment of the present disclosure, the network device maydetermine a resource mapping corresponding to the resource allocationtype from a plurality of resource mappings of PTRS transmission for aplurality of resource allocation types. Further, it is also possible tofurther obtain the PTRS transmission resource configuration parameterbased on the resource mapping. For example, there can be a mappingscheme for RA type 0, another mapping scheme for RA type 2 withlocalized mode, and a further mapping scheme for RA type 2 withdistributed mode. That is to say, the plurality of resource mappingsfurther comprises different resource mappings for different allocationmodes in the same resource allocation type.

In addition, it is also possible to adopt other mapping schemes. Forexample, it is also possible that Type 2 with distributed mode can sharethe common mapping scheme with RA type 0. As another example, it is alsopossible that RA type 0 can be divided into different allocation modeswhich could use different mapping schemes.

In a further embodiment of the present disclosure, the PTRS transmissionresource configuration parameter can be associated with sizes ofrespective resource segments within allocated transmission resources.For example, for RA Type 0 (bitmap), the PTRS frequency density can beassociated with the size of the resource segment, i.e. the number of thecontinuous PRB, or the size of RBG.

Regarding the example mappings, reference could be made to relevantcontents described for the terminal device and detailed description willbe omitted therein for purpose of simplification. In addition, it can beunderstand that for the PTRS transmission resource configurationparameter determination at the network device, most of operations aresimilar to those at the terminal device except those configurationinformation and RA type indication which are corresponding to those atthe terminal device. Thus, for details about the operations at thenetwork device, one may refer to those descriptions with regard to theterminal device.

Thus, it can be seen that, with embodiments of the present disclosure,it may determine different PTRS configuration parameters for differentresource allocation types, and thus provide a more suitable PTRSconfiguration solution for different resource allocation cases.

In addition, in the NR system, it was also agreed to adopt a singlePDCCH or multiple PDCCHs to schedule PDSCH from different TRPs.Particularly, single NR-PDCCH can schedule a single NR-PDSCH whereseparate layers are transmitted from separate TRPs; multiple NR-PDCCHscan each schedule a respective NR-PDSCH wherein each NR-PDSCH istransmitted from a separate TRP. The case, in which each layer istransmitted from all TRPs jointly and single NR-PDCCH schedules singleNR-PDSCH can be done in a spec-transparent manner. However, some issuesmight be caused when two TRPs transmit the same PDSCH to UE. Forexample, phase noises from the two TRPs are difficult to bedistinguished from each other and thus it is hard to compensate thephase noises.

As illustrated in FIG. 8 , in such a case, the DMRS configurations (e.g.ports, sequences, etc.) will be identical and the equivalent channel canbe represented by:(H1*P1+H2*P2),  (equation 1)wherein, H1 and H2 represents channel transfer functions of the twochannels and P1 and P2 represents the precoders used for the twochannels respectively. The phase noise in different symbols is exp(j*α)for TPR 1 and the phase noise is exp(j*β) for TRP 2. In this case, ifseparate PTRSs are transmitted from separate TRPs, PTRS transmissionwill be performed in a non-transparent manner. While if the same PTRS istransmitted from separate TRPs, phase noises from the two TRPs is hardto be distinguished from each other and thus the phase noises cannot bewell compensated. For example, in time interval 1, the received PTRS is(H1*P1+H2*P2)*S1,  (equation 2)in time interval 2, the channel is(H1*exp(j*α1)*P1+H2*exp(j*β1)*P2)*S2  (equation 3)

In such a case, parameters α1 and β1 cannot be estimated from same PTRStransmission.

In an embodiment of the present disclosure, it is proposed that only oneTRP transmits PTRS at the PTRS position, as illustrated in FIG. 9 .Since only one TRP transmits the PTRS, parameter α1 can be estimated andthus the estimated channel can be represented by(H 1*P 1+H 2*exp(j*(β1−α1))*P 2)*S2.  (equation 4)

Thus, in such a case, at least channel from one TRP can be estimatedaccurately and well compensated.

In another embodiment of the present disclosure, different TRPs cantransmit PTRS but the transmissions are performed at different PTRSpositions, as illustrated in FIG. 10A. As an example, these TRPs cantake turns at transmitting PTRS at the potential PTRS positions, asillustrated in FIG. 10B. In such a case, it is also possible to increasethe frequency density. That is to say, the UE can be configured withPTRS with higher density if the multiple TRPs transmit all layers to theUE. In this way, at one time, at least there is one channel from one TRPthat can be estimated accurately and well compensated. Or alternatively,average phase noise from two TRPs can be used for CPE compensation. Forexample, (α1+β1)/2 can be estimated and the estimated channel can be(H 1*exp(j*(α1−β1)/2)*P 1+H 2*exp(j*(β1−α1)/2)*P 2)*S2.  (equation 5)

In such a case, it can achieve a better compensation as well.

In a further embodiment of the present disclosure, separate DMRS and/orPTRS design are used to this scenario. Separate DMRS and/or PTRS designfor this scenario.

For PTRS, more PTRS ports can configured for this scenario. For example,there are N ports for PTRS, and N/2 from TRP1 and N/2 from TRP2, asillustrated in FIG. 11 . As another example, orthogonal PTRS ports canbe kept unchanged; PTRS from different TRPs are transmitted on the sameREs, but the sequences for transmitting the PTRS can be different. Insuch a case, for example, average phase noise from two TRPs can be usedfor compensation.

Additionally, or alternatively, for DMRS, more DMRS ports can beconfigured for this scenario. For example, there are N ports for DMRS,and N/2 from TRP1 and N/2 from TRP2. As another example, orthogonal PTRSports can be kept unchanged; DMRS from different TRPs are transmitted onthe same REs, but the sequences for transmitting the DMRS can bedifferent.

With this solution, UE can estimate channels and/or phase noise for eachTRP.

In addition, in a further embodiment of the present disclosure, the TRPsmay exchange phase noise information. By means of exchange of the phasenoise information, a TRP may learn phase noise and this information canbe used during transmitting the PTRS so that the multiple TRPs havesubstantially the same or similar phase noise, when observed by UE. Oralternatively, one TRP may transmit PTRS to other TRPs, which mayreceive the PTRS, and estimate the phase noise. Then the TRPs maytransmit signals or channels multiplied with the estimated phase noisevalues.

FIG. 12 further illustrates an apparatus for determining PTRStransmission resource configuration parameter at a terminal deviceaccording to an embodiment of the present disclosure. Apparatus 1200 canbe implemented at a terminal device such as UE.

As illustrated in FIG. 12 , apparatus 1200 comprises a parameterdetermination module 1201. The parameter determination module 1201 maybe configured to determine a PTRS transmission resource configurationparameter based on a resource allocation type to be used in datatransmission.

In an embodiment of the present disclosure, the parameter determinationmodule 1201 may be further configured to determine, from a plurality ofassociation tables of PTRS transmission resource configuration parameterfor a plurality of resource allocation types, an association tablecorresponding to the resource allocation type; and obtain the PTRStransmission resource configuration parameter from the associationtable.

In another embodiment of the present disclosure, the plurality ofassociation tables may further comprise different association tablesconfigured for different allocation modes in the same resourceallocation type.

In a further embodiment of the present disclosure, apparatus 1200 mayfurther comprise a configuration receiving module 1202. Theconfiguration receiving module 1202 may be configured to receiveconfiguration information on the plurality of association tables of PTRStransmission resource configuration parameter from a network device.

In a still further embodiment of the present disclosure, the parameterdetermination module 1201 may be further configured to determine, from aplurality of resource mappings of PTRS transmission for a plurality ofresource allocation types, a resource mapping corresponding to theresource allocation type; and determine the PTRS transmission resourceconfiguration parameter based on the resource mapping.

In a yet further embodiment of the present disclosure, the plurality ofresource mappings may further comprise different resource mappings fordifferent allocation modes in the same resource allocation type.

In a yet still further embodiment of the present disclosure, the PTRStransmission resource configuration parameter may be associated withsizes of respective resource segments within allocated transmissionresources.

FIG. 13 illustrates a block diagram of determining a PTRS configurationparameter at a network device according to an embodiment of the presentdisclosure. As illustrated in FIG. 1300 , apparatus 1300 may comprise aparameter determination module 1301. The parameter determination module1301 may be configured to determine a PTRS transmission resourceconfiguration parameter based on a resource allocation type to be usedin data transmission.

In an embodiment of the present disclosure, the parameter determinationmodule 1301 may be configured to determine, from a plurality ofassociation tables of PTRS transmission resource configuration parameterfor a plurality of resource allocation types, an association tablecorresponding to the resource allocation type; and obtain the PTRStransmission resource configuration parameter from the associationtable.

In another embodiment of the present disclosure, the plurality ofassociation tables may further comprise different association tablesconfigured for different allocation modes in the same resourceallocation type.

In a further embodiment of the present disclosure, apparatus 1300 mayfurther comprise a configuration transmission module 1302. Theconfiguration transmission module 1302 may be configured to transmitconfiguration information on the plurality of association tables of PTRStransmission resource configuration parameter to a terminal device.

In a still further embodiment of the present disclosure, the parameterdetermination module 1301 may be configured to determine, from aplurality of resource mappings of PTRS transmission for a plurality ofresource allocation types, a resource mapping corresponding to theresource allocation type; and determine the PTRS transmission resourceconfiguration parameter based on the resource mapping.

In a yet further embodiment of the present disclosure, the plurality ofresource mappings may further comprise different resource mappings fordifferent allocation modes in the same resource allocation type

In still yet further embodiment of the present disclosure, the PTRStransmission resource configuration parameter may be associated withsizes of respective resource segments within allocated transmissionresources

Hereinbefore, the apparatuses 1200 and 1300 are described with referenceto FIGS. 12 and 13 in brief. It is noted that the apparatuses 1200 and1300 may be configured to implement functionalities as described withreference to FIGS. 3 to 11 . Therefore, for details about the operationsof modules in these apparatuses, one may refer to those descriptionsmade with respect to the respective steps of the methods with referenceto FIGS. 3 to 11 .

It is further noted that components of the apparatuses 1200 and 1300 maybe embodied in hardware, software, firmware, and/or any combinationthereof. For example, the components of apparatuses 1200 and 1300 may berespectively implemented by a circuit, a processor or any otherappropriate selection device.

Those skilled in the art will appreciate that the aforesaid examples areonly for illustration not limitation and the present disclosure is notlimited thereto; one can readily conceive many variations, additions,deletions and modifications from the teaching provided herein and allthese variations, additions, deletions and modifications fall theprotection scope of the present disclosure.

In addition, in some embodiment of the present disclosure, apparatuses700 and 800 may comprise at least one processor. The at least oneprocessor suitable for use with embodiments of the present disclosuremay include, by way of example, both general and special purposeprocessors already known or developed in the future. Apparatuses 1200and 1300 may further comprise at least one memory. The at least onememory may include, for example, semiconductor memory devices, e.g.,RAM, ROM, EPROM, EEPROM, and flash memory devices. The at least onememory may be used to store program of computer executable instructions.The program can be written in any high-level and/or low-level compliableor interpretable programming languages. In accordance with embodiments,the computer executable instructions may be configured, with the atleast one processor, to cause apparatuses 1200 and 1300 to at leastperform operations according to the method as discussed with referenceto FIGS. 3 to 11 respectively.

FIG. 14 further illustrates a simplified block diagram of an apparatus1410 that may be embodied as or comprised in a network device like abase station in a wireless network and an apparatus 1420 that may beembodied as or comprised in a terminal device like UE as describedherein.

The apparatus 1410 comprises at least one processor 1411, such as a dataprocessor (DP) and at least one memory (MEM) 1412 coupled to theprocessor 1411. The apparatus 1410 may further comprise a transmitter TXand receiver RX 1413 coupled to the processor 1411, which may beoperable to communicatively connect to the apparatus 1420. The MEM 1412stores a program (PROG) 1414. The PROG 1414 may include instructionsthat, when executed on the associated processor 1411, enable theapparatus 1410 to operate in accordance with embodiments of the presentdisclosure, for example the method 700. A combination of the at leastone processor 1411 and the at least one MEM 1412 may form processingmeans 1415 adapted to implement various embodiments of the presentdisclosure.

The apparatus 1420 comprises at least one processor 1421, such as a DP,and at least one MEM 1422 coupled to the processor 1421. The apparatus1420 may further comprise a suitable TX/RX 1423 coupled to the processor1421, which may be operable for wireless communication with theapparatus 1410. The MEM 1422 stores a PROG 1424. The PROG 1424 mayinclude instructions that, when executed on the associated processor1421, enable the apparatus 1420 to operate in accordance with theembodiments of the present disclosure, for example to perform the method300. A combination of the at least one processor 1421 and the at leastone MEM 1422 may form processing means 1425 adapted to implement variousembodiments of the present disclosure.

Various embodiments of the present disclosure may be implemented bycomputer program executable by one or more of the processors 1411, 1421,software, firmware, hardware or in a combination thereof.

The MEMs 1412 and 1422 may be of any type suitable to the localtechnical environment and may be implemented using any suitable datastorage technology, such as semiconductor based memory devices, magneticmemory devices and systems, optical memory devices and systems, fixedmemory and removable memory, as non-limiting examples.

The processors 1411 and 1421 may be of any type suitable to the localtechnical environment, and may include one or more of general purposecomputers, special purpose computers, microprocessors, digital signalprocessors DSPs and processors based on multicore processorarchitecture, as non-limiting examples.

In addition, the present disclosure may also provide a carriercontaining the computer program as mentioned above, wherein the carrieris one of an electronic signal, optical signal, radio signal, orcomputer readable storage medium. The computer readable storage mediumcan be, for example, an optical compact disk or an electronic memorydevice like a RAM (random access memory), a ROM (read only memory),Flash memory, magnetic tape, CD-ROM, DVD, Blue-ray disc and the like.

The techniques described herein may be implemented by various means sothat an apparatus implementing one or more functions of a correspondingapparatus described with one embodiment comprises not only prior artmeans, but also means for implementing the one or more functions of thecorresponding apparatus described with the embodiment and it maycomprise separate means for each separate function, or means that may beconfigured to perform two or more functions. For example, thesetechniques may be implemented in hardware (one or more apparatuses),firmware (one or more apparatuses), software (one or more modules), orcombinations thereof. For a firmware or software, implementation may bemade through modules (e.g., procedures, functions, and so on) thatperform the functions described herein.

Exemplary embodiments herein have been described above with reference toblock diagrams and flowchart illustrations of methods and apparatuses.It will be understood that each block of the block diagrams andflowchart illustrations, and combinations of blocks in the blockdiagrams and flowchart illustrations, respectively, can be implementedby various means including computer program instructions. These computerprogram instructions may be loaded onto a general purpose computer,special purpose computer, or other programmable data processingapparatus to produce a machine, such that the instructions which executeon the computer or other programmable data processing apparatus createmeans for implementing the functions specified in the flowchart block orblocks.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyimplementation or of what may be claimed, but rather as descriptions offeatures that may be specific to particular embodiments of particularimplementations. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable sub-combination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a sub-combination or variation of a sub-combination.

It will be obvious to a person skilled in the art that, as thetechnology advances, the inventive concept can be implemented in variousways. The above described embodiments are given for describing ratherthan limiting the disclosure, and it is to be understood thatmodifications and variations may be resorted to without departing fromthe spirit and scope of the disclosure as those skilled in the artreadily understand. Such modifications and variations are considered tobe within the scope of the disclosure and the appended claims. Theprotection scope of the disclosure is defined by the accompanyingclaims.

What is claimed is:
 1. A method performed by a terminal device,comprising: determining a Phase Tracking Reference Signal (PTRS)transmission resource configuration parameter based on a waveform typeto be used in data transmission, comprising determining, from aplurality of resource mappings of PTRS transmission, a resource mappingcorresponding to a waveform type; and determining the PTRS transmissionresource configuration parameter based on the resource mapping; andtransmitting the PTRS based on the determined PTRS transmission resourceconfiguration parameter.
 2. A method performed by a network device,comprising: transmitting a Phase Tracking Reference Signal (PTRS)transmission resource configuration parameter to be used in datatransmission, wherein the PTRS transmission resource configurationparameter is associated with a resource mapping, among a plurality ofresource mappings, corresponding to a waveform type; and receiving thePTRS based on the PTRS transmission resource configuration parameter,wherein each of the plurality of resource mappings is for a differentallocation mode in the same waveform type.
 3. The method of claim 1,further comprising determining, from the plurality of resource mappingsof PTRS transmission for a plurality of allocation modes based on thewaveform type, the resource mapping corresponding to the allocationmode.
 4. A terminal device, comprising: a processor configured todetermine, from a plurality of resource mappings of Phase TrackingReference Signal (PTRS) transmission, a resource mapping correspondingto a waveform type; and determine a PTRS transmission resourceconfiguration parameter based on the resource mapping; and a transmitterconfigured to transmit the PTRS based on the determined PTRStransmission resource configuration parameter.